Sonication accelerated formation of Mg-Al-phosphate layered double hydroxide via sol-gel prepared mixed metal oxides

Abstract

Single-phase magnesium-aluminium layered double hydroxide (LDH) intercalated with dihydrogen phosphate was successfully produced by hydration of nanopowder of the respective mixed metal oxide (MMO) obtained using sol-gel based method followed by a two-step anion exchange hydroxide-to-chloride and chloride-to-phosphate. The MMO with the metal cation ratio of Mg/Al = 2:1 was prepared using the aqueous sol-gel method. Processes of the parent Mg 2 Al-OH LDH formation and the successive anion-exchanges, ОН − → Cl − and Cl − → H 2 PO 4 − , were considerably accelerated via the application of high-power (1.5 kW) ultrasound. The crystalline phases formed at all stages of the Mg 2 Al-H 2 PO 4 LDH production were characterized using X-ray diffraction, scanning electron microscopy, scanning transmission electron microscopy, inductive coupled plasma optical emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. Based on the data of chemical analysis and the XRD data, the type of the intercalated phosphate anion was determined and the arrangement of this anion in the interlayer was modelled.

Characterization and Efficacy of A Novel Formula of Insulin Chitosan Layered Duple Hydroxide-Nanohybrid for Oral Administration

“…The XRD of chitosan exhibited the semi-crystalline nature of chitosan with two distinct peaks at 2θ = 10° and 50° due to (020) and (110), respectively. The XRD of LDH-INS-CSNPs showed a diffraction peak shifting of (003) and (006) specifying the synergy between chitosan and LDH [28]. Besides, the disappearance of the small diffracted peaks of LDH may refer to one of the following reasons: removal of water molecules, rearrangement of Zn/Al ions, and / or adsorption of insulin molecules on the surface of LDH.…”

Cast iron corrosion protection with chemically modified Mg Al layered double hydroxides synthesized using a novel approach

“…Obtained LDH were Mg(2)Al-OH and Mg(2)Al-10%Ce-OH. It was recently shown that direct hydroxide-to-phosphate anion exchange is unlikely but can be implemented via formation of the intermediate chlorine-intercalated phase [14].…”

“…1 g of the Mg(2)Al-Cl powder was immersed in the solution followed by addition of NaH 2 PO 4 to adjust the pH value to 7.5. At such conditions, the intercalated anion is dihydrogen phosphate, H 2 PO 4 - [14]. The reaction was sonication-assisted and took 8 min.…”

“…Three samples were tested for each the above-mentioned solutions to ensure reproducibility of the measurements. H 2 PO 4 suggests that the phosphate anion is arranged in a such way that a line along its maximum dimension is perpendicular to the layer plane [14].…”

Insight into the Role of Cerium (III) Addition to a MgAl-LDH Coating on AA6082

“…The general formula of an LDH is expressed as [M M (OH) ] (X ) / ⋅ mH O where M and M are divalent and trivalent metal cations, respectively, stands for the molar ratio M /(M + M ) and X represents an anion having charge [35]. Usually, the divalent and trivalent metal cations are Mg , Zn , Cu , Mn , Co , Al , Cr and Fe ions but also lanthanides and bismuth, having comparable ionic radii, can isomorphically substitute the trivalent metallic cations [36]. For what concern the inter-domain anions, F , Cl Br , I , oxides as NO , CO , sulfates and chromates or more complex organic and inorganic compounds can be present as counterbalancing species.…”